Lean Production

The fundamental concept of lean production is quite simple: consistently focus on removing waste from the manufacturing process, all while maintaining high quality. This approach can be implemented across all areas of a company, starting from design and continuing through production and distribution.

This strategy can make the operation run more smoothly, by using feedback from employees and customers to better use resources and simplify processes. Learning about this way of managing production can help you figure out if it's right for your organization and help you reach your objectives.

This methodology was first developed by the Toyota Motor Corporation in the 1950s-60s, who titled their revolutionary manufacturing principle the Toyota Production System. 

8 Wastes of Lean Production 

Japanese industrial engineer and businessman Taiichi Ohno is considered the father of the TPS, established seven common types of wastes in mass manufacturing, processes, and resources that do not add value for the customers:

1. Defects
2. Excessive processing
3. Overproduction
4. Waiting
5. Motion
6. Inventory
7. Transportation

Today, many lean professionals also include an 8th waste: non-utilized talent. Let’s understand each in detail: 

1. Defects

   If a product isn't made correctly, it can't be used as intended, and this often means it needs to be fixed or scraped away, which adds extra costs to the production process without delivering any value to the customer.

2. Excessive Processing 

   It happens when more work or features are added to a product or service than what the customer needs. This can include using more expensive or higher precision equipment, adding extra parts, doing added checks or analyses, making something more complicated than necessary, and including unnecessary features or functions. 

3. Overproduction 

   Making more of a product or component than what is currently needed can result in a host of problems, such as blocking the flow of work, higher costs for storage, hiding any defects in the product, requiring more capital to fund the entire manufacturing process, and it increases the time it takes to get the product to the customer.

4. Waiting 

   When things or people are not ready for the next step in the production process, it can cause delays, and this waiting can result in extra costs for the company, such as paying workers for their time when they have nothing to do or rushing to get things done quickly. There can also be additional expenses for overtime pay, expediting expenses, and the procurement of necessary parts.

5. Motion

   When people, tools, or machines move excessively during work, it's called "waste in motion." This can include things like walking, lifting, bending, and stretching; if a task involves a lot of unnecessary movement, it should be redesigned to make the work easier and improve safety.

6. Inventory

   Having more inventory on hand than needed can create issues, such as product defects or damaged goods, longer wait times for production, wasting money on resources, and problems being hidden away within the stored items. Excessive inventory can be caused by purchasing surplus material, overproducing work-in-process (WIP), or creating more products than the customer requires.

7. Transportation

   Transportation waste includes more than necessary movements of people, tools, inventory, equipment, or products, and this excessive movement of materials can result in product damage or defects. Additionally, when people and equipment move too much, it can cause unnecessary work, greater wear and tear, and exhaustion. 

8. Non-Utilized Talent 

   While not originally included in the Toyota Production System (TPS), the "waste of human potential" or the "8th waste" refers to not fully using people's skills, ideas, and creativity in the workplace. This often happens when managers don't involve frontline employees in problem-solving and process improvement. Since these workers are most familiar with the daily operations, they can spot issues and come up with smart solutions, which can improve efficiency and productivity.

Lean vs. Six Sigma

Lean and six sigma are two different yet complementary approaches to improving business processes and overall efficiency. Let us provide an overview of the key differences between these two methodologies:

Lean Methodology: 

Focus: Eliminating waste and non-value-added activities in processes to improve efficiency and productivity.

Key Principles: Identifying and removing the seven types of waste (overproduction, waiting, transportation, over-processing, inventory, motion, and defects).

Emphasis: Streamlining workflows, reducing lead times, and improving flow through the system.

Typical Tools: Value stream mapping, 5S, kanban, kaizen, and just-in-time production.

Six Sigma Methodology:

Focus: Reducing variation and defects in processes to improve quality and customer satisfaction.

Key Principles: Defining, measuring, analyzing, improving, and controlling (DMAIC) processes.

Emphasis: Using statistical and data-driven techniques to identify and eliminate the root causes of problems.

Typical Tools: DMAIC, process capability analysis, statistical process control, design of experiments, and failure mode and effects analysis.

Key Differences

Lean Production Philosophies 

TPS was built upon two foundational philosophies to address these wastes as well as the waste of mura (uneven or irregular production levels) and muri (overworked employees or machines):

Toyota found great success with this new way of manufacturing becoming one of the top leaders in the automobile industry. The combination of Toyota sharing TPS with other organizations in the 1990s and the 1990 publication The Machine That Changed the World introduced the rest of the world to these groundbreaking concepts, effectively setting the stage for Lean production.

Lean Production Tools and Concepts

Lean production systems use many of the tools and strategies developed by the Toyota Motor Corporation:

Kaizen: It is a continuous improvement mindset believing that processes can always be improved and that making continuous small improvements will have a major impact over time.

Heijunka: It is a Japanese term meaning production or production smoothing. Essential for Just-in-Time production and an effective Kanban system, Heijunka eliminates waste by manufacturing batches as small as possible and leveling production either by volume or product.

Kanban: It is the operating component of a just-in-time production system. Kanban cards and bins are sent down the line to streamline processes and keep batch sizes small and production only happens when the visual cue is sent to trigger an action.

5S: It is sometimes thought of as a housekeeping strategy for facilities, factories, and warehouses. Although at its core 5S is based on organization, it is a strategy that works to meet the Lean goals of eliminating waste.

Gemba Walks and Genchi Genbutsu: These are two principles that fall under the same philosophy, the concept is that the most effective way management and leaders can understand issues, or their production line is by going and observing the process up close.

5s of Lean Production

5S is a Lean Production methodology that focuses on organizing workplaces for efficiency and effectiveness, and it consists of five steps, each starting with the letter "S" in Japanese: Seiri, Seiton, Seiso, Seiketsu, and Shitsuke.

Seiri, or "Sort,”: Categorizing and separating necessary items from unnecessary ones to eliminate clutter and making sure that only necessary items are kept in the workspace.

Seiton, or "Straighten,": Arranges items in a logical, accessible, and orderly manner to make it easy to find and put away tools and materials, reducing wasted time and motion.

Seiso, or "Shine,": Clean and inspect the workspace regularly to identify issues and maintain a safe, clean, and productive work environment.

Seiketsu, or "Standardize,": Creating and maintaining standard work practices, so that everyone follows the same procedures to promote consistency, efficiency, and continuous improvement.

Shitsuke, or "Sustain,": Developing habits and a culture of continuous improvement so that the 5S principles are integrated into daily work practices.

Advantages and Disadvantages of Lean Production 

As you may already know, lean production philosophy revolves around the elimination of waste in the workplace. Here are some of the advantages and disadvantages of lean manufacturing.

Advantages

• Elimination of Waste

  The goal of Lean principles is to get rid of waste that impacts production and resources. Some wastes are easy to spot and fix, like a machine that's not working properly and making lots of errors. Other wastes are more about the environment workers are in. For example, better lighting can help workers read instructions more clearly. 

• Employee Satisfaction

  Involving your production staff is crucial when implementing lean principles in your company because they have valuable insights into identifying waste and other problems. Actively engage them in improvement processes and welcome their suggestions so you can get a positive response and a sense of ownership and satisfaction in their contributions.

• Just in Time 

  Just in Time (JIT), strategy suggests large inventories are wasteful due to their excessive use of company resources. Holding surplus inventory ties up business equity and impacts cash flow. Implementing JIT minimize warehousing requirements and optimize the timing of raw material procurement and product delivery. 

• Competitive Edge 

  Implementing lean production methods not only lowers costs and increases efficiency but also brings changes in the workplace that can create new sales. You can use warehouse space savings for new product lines and apply time savings to take on additional tasks and respond quickly to shifts in customer needs. Producing high-quality products in small amounts, without waste, and on schedule, gives you a competitive edge over other businesses.

Disadvantages

• Overusage of Lean 

  More than necessary reliance on lean techniques can backfire. If monitoring productivity and waste begins to hinder production time, the solution becomes the problem. 

• Systemic Bottlenecks 

  JIT principles are most effective when applied to stable system components. When delivery times for raw materials and finished goods are predictable, production can be scheduled accordingly. However, excessive aggressiveness in JIT scheduling increases the risk of system bottlenecks. Unforeseen supplier issues or maintenance emergencies can disrupt production flow, and failure to consider limitations in JIT planning can have serious consequences for the entire system. 

• Worker Frustration

  When a certain efficiency level is reached, pushing for additional improvements with lean methods can demotivate workers. Signs of backsliding in past achievements might suggest worker dissatisfaction. Maintaining the right balance between maintaining the status quo and continuous improvement is tricky in a lean work environment.